Pre deparure battery pre heat. What temperature? Best way to preheat?

[exlatccatsa]

As the evenings are starting to cool down and some mornings are getting well down into single figures. I thought I'd try to find the definitive answer to the Question:
Below what OAT does the battery need pre heating? and What is the best way to pre heat the battery?

 

[NorfolkMustard]

I can’t remember exactly, but I think it’s something like 15°C

charging will warm it a bit, although 2kW won’t do much at all, 7kW may.

best way for a quick battery warm up though is to turn on the climate remotely. Car can be plugged in for this but if it’s actively charging then it won’t prioritise battery warming.

 

[Tonybvi]

I live in Aberdeenshire and for the past few days with temperatures between 9 and 14 deg C I have seen the restricted regen sign up on my display. First time it has shown since lockdown started in March. I now simply start the car charging about half an hour before I need to use it.

 

[exlatccatsa]

So here outside Aberdeen that'll mean most days? and almost every day in Shetland?
and charging is the most effective way?

 

[Tonybvi]

So here outside Aberdeen that'll mean most days? and almost every day in Shetland?

Yep!!

 

[NorfolkMustard]

Here's a thread I posted on it from last year

Morning warm-up - comparing 2019.40.2 v. 2019.40.50

and a graph of it using energy to warm the battery when turning on climate remotely

12kW initially, down to 9kW for about 30 mins. This was when it was 0ºC out

It was "is_preconditioning" for about 40 mins in total (green dashed line between ~08:06 -> 08:48 but the last 10 mins (08:38->08:48) it was (presumably) just pumping round the previously warmed coolant still.

 

[exlatccatsa]

Thanks, Going to try and attempt the 285 miles Kemnay to Tebay again next week and battery preheat will be crucial as we hit the cooler weather.
There's a lot going on in that graph but its very interesting and informative.
Thanks

 

[Tonybvi]

I do a similar trip (from Banchory to Preston) via Tebay fairly regularly in a Raven MX.
As I need a full battery to do it I find that charging to 90% the day before then the final 10% charge set to finish immediately before I leave works fine. This avoids having the battery sitting for a long period at a very high soc and also preconditions it nicely for when I leave.

 

[MorrisonHiker]

The method many use is preheat the battery is to time charging so that it finishes close to departure time. Sometimes I will lower the amps slightly so that charging takes longer and ensures the car is still charging when I'm ready to leave.

 

[Adopado]

As the evenings are starting to cool down and some mornings are getting well down into single figures. I thought I'd try to find the definitive answer to the Question:
Below what OAT does the battery need pre heating? and What is the best way to pre heat the battery?

Just for clarity the battery doesn't actually "need" pre-heating. The battery will warm up with normal driving. The advantage of giving it a chance to start warming is to optimise range (if you can do the pre-warm whilst still plugged in). It will also allow the car to have stronger regen sooner than it would otherwise and to release full power earlier (you may need a stopwatch to tell the difference!) When it's properly winter cold then doing the pre heat by initiating climate from the app gives you a warm cabin and the bonus of warmer battery with optimised range (if warming when plugged in). There is no obvious advantage from pre heating if not plugged in other than to make the cabin comfortable.

 

[ben_c]

Just for clarity the battery doesn't actually "need" pre-heating. The battery will warm up with normal driving. The advantage of giving it a chance to start warming is to optimise range (if you can do the pre-warm whilst still plugged in). It will also allow the car to have stronger regen sooner than it would otherwise and to release full power earlier (you may need a stopwatch to tell the difference!) When it's properly winter cold then doing the pre heat by initiating climate from the app gives you a warm cabin and the bonus of warmer battery with optimised range (if warming when plugged in). There is no obvious advantage from pre heating if not plugged in other than to make the cabin comfortable.

I wish it’d only precondition the battery when plugged in!

 

[Adopado]

I wish it’d only precondition the battery when plugged in!

I'm not 100% sure but I don't think it specifically pre-warms the battery when the climate is switched on but the car is not plugged in ... I always thought it just gained a little as a by-product of the normal cabin warming ... I'm sure Bjorn Nyland will have tested for this if you want to dig around Youtube.

 

[M3noob]

Alternatively, if you are near a SuperCharger, tell the car a little white lie that you are on the way there. Whenever I've headed to an SC I get the pre-warming message about 20 minutes/miles out.

 

[ben_c]

I'm not 100% sure but I don't think it specifically pre-warms the battery when the climate is switched on but the car is not plugged in ... I always thought it just gained a little as a by-product of the normal cabin warming ... I'm sure Bjorn Nyland will have tested for this if you want to dig around Youtube.

it definitely does, you can hear the whine of the drive motors (used to generate the heat).

 

[Jeeves]

What is the best way to pre heat the battery?

There’s a section in the manual entitled ‘Cold Weather Best Practices’. In addition:

• Have car plugged in, nobody inside and locked. Sitting inside seems to prevent battery warming.
  
• Turn climate on via app.
• Leave for 30 mins or so. Time required depends on how cold the car is and the outside temperature. 30 minutes should be plenty unless we have a serious cold snap.

More info on what the car does in Bjørn Nyland’s videos such as this one. The car draws a maximum of about 13kW until the cabin gets warm and then drops to about 6kW when just heating the battery.

 

[exlatccatsa]

I do a similar trip (from Banchory to Preston) via Tebay fairly regularly in a Raven MX.
As I need a full battery to do it I find that charging to 90% the day before then the final 10% charge set to finish immediately before I leave works fine. This avoids having the battery sitting for a long period at a very high soc and also preconditions it nicely for when I leave.

Do you go over Cairn o Mount on that route Tony? I came back from Montrose thay way on Friday and saved 6% versus the bypass, although it took a little longer. I may try that again on the next trip to Montrose on Friday.

 

[exlatccatsa]

Just for clarity the battery doesn't actually "need" pre-heating. The battery will warm up with normal driving. The advantage of giving it a chance to start warming is to optimise range (if you can do the pre-warm whilst still plugged in). It will also allow the car to have stronger regen sooner than it would otherwise and to release full power earlier (you may need a stopwatch to tell the difference!) When it's properly winter cold then doing the pre heat by initiating climate from the app gives you a warm cabin and the bonus of warmer battery with optimised range (if warming when plugged in). There is no obvious advantage from pre heating if not plugged in other than to make the cabin comfortable.

I was just looking to minimise the time in the 4 and 500 wh/mile on the regular 7 mile trip to Inverurie at 06:30 and 23:00 especially in the winter. Thanks for the info.

 

[exlatccatsa]

There’s a section in the manual entitled ‘Cold Weather Best Practices’. In addition:

• Have car plugged in, nobody inside and locked. Sitting inside seems to prevent battery warming.
  
• Turn climate on via app.
• Leave for 30 mins or so. Time required depends on how cold the car is and the outside temperature. 30 minutes should be plenty unless we have a serious cold snap.

More info on what the car does in Bjørn Nyland’s videos such as this one. The car draws a maximum of about 13kW until the cabin gets warm and then drops to about 6kW when just heating the battery.

Thanks, I'm sure this will be a useful thread for the coming winter.

 

[Jason71]

I was just looking to minimise the time in the 4 and 500 wh/mile on the regular 7 mile trip to Inverurie at 06:30 and 23:00 especially in the winter. Thanks for the info.

Since I use octopus go at 5p/kwh over night to charge, unless I am on a long journey and need range, I just pre heat for 10 minutes to get the cabin warm. Doing more while plugged in seems a waste of day rate electricity. And doing unplugged has no big advantage.

 

[Adopado]

Since I use octopus go at 5p/kwh over night to charge, unless I am on a long journey and need range, I just pre heat for 10 minutes to get the cabin warm. Doing more while plugged in seems a waste of day rate electricity. And doing unplugged has no big advantage.

Yes, and I hope everyone realises that this issue in the various posts above is really related to proper winter cold not the cool weather that's around just now. The only pre heating needed (even if you get a regen reduced message on screen) is for your own comfort.